Development and validation of a new drag law using mechanical energy balance approach for DEM–CFD simulation of gas–solid fluidized bed

TY - JOUR

T1 - Development and validation of a new drag law using mechanical energy balance approach for DEM–CFD simulation of gas–solid fluidized bed

AU - Ayeni, O. O.

AU - Wu, C. L.

AU - Nandakumar, K.

AU - Joshi, J. B.

N1 - Publisher Copyright: © 2016 Elsevier B.V.

PY - 2016

Y1 - 2016

N2 - DEM–CFD simulations of a gas–solid fluidized bed are presented and compared to experimental results of the small scale challenge problem (SSCP) from the National Energy Technology Laboratory. It has been well recognized that the pressure drop and the solid velocity profile across the bed may be over-predicted with the widely used constitutive relations for gas–solid flows in the Eulerian two-fluid frame work. An attempt is made to address this problem using energy and force balances across a bubbling fluidized bed to attenuate the drag coefficient while preserving the correct velocity profile. This is done with the DEM model for particulate phase and the new drag law is applied to the Lagrangian–Eulerian model for particulate flows. We show that a drag model used in simulating gas–solid fluidized bed should account for the energy dissipation in both a particle-rich and particle-lean (bubbles and slugs) regions of the fluidized bed. The new drag model proposed in this work has taken into account the additional energy dissipation from forming heterogeneous structures and performs better than the standard closure models used for bubbling fluidized bed simulations in the selected cases we have examined against NETL data. Such approaches to closure model building enforce the macroscopic conservation principles while attempting to still accommodate local variations in drag due to cluster formation mechanisms.

AB - DEM–CFD simulations of a gas–solid fluidized bed are presented and compared to experimental results of the small scale challenge problem (SSCP) from the National Energy Technology Laboratory. It has been well recognized that the pressure drop and the solid velocity profile across the bed may be over-predicted with the widely used constitutive relations for gas–solid flows in the Eulerian two-fluid frame work. An attempt is made to address this problem using energy and force balances across a bubbling fluidized bed to attenuate the drag coefficient while preserving the correct velocity profile. This is done with the DEM model for particulate phase and the new drag law is applied to the Lagrangian–Eulerian model for particulate flows. We show that a drag model used in simulating gas–solid fluidized bed should account for the energy dissipation in both a particle-rich and particle-lean (bubbles and slugs) regions of the fluidized bed. The new drag model proposed in this work has taken into account the additional energy dissipation from forming heterogeneous structures and performs better than the standard closure models used for bubbling fluidized bed simulations in the selected cases we have examined against NETL data. Such approaches to closure model building enforce the macroscopic conservation principles while attempting to still accommodate local variations in drag due to cluster formation mechanisms.

KW - Computational fluid dynamics

KW - Discrete element method

KW - Drag model

KW - Fluidized bed

KW - Gas–solid flow

UR - http://www.scopus.com/inward/record.url?scp=84979670932&partnerID=8YFLogxK

U2 - 10.1016/j.cej.2016.05.056

DO - 10.1016/j.cej.2016.05.056

M3 - 文章

AN - SCOPUS:84979670932

SN - 1385-8947

VL - 302

SP - 395

EP - 405

JO - Chemical Engineering Journal

JF - Chemical Engineering Journal

ER -